Pages with mixed content (mixed content) are site pages opened via the HTTPS protocol, some elements of which (for example, styles, scripts, images) are requested via links with the HTTP protocol. The browser marks such pages as unprotected or incompletely protected and may block the loading of such elements. As a result, the site may be displayed or work incorrectly.
You can view information about the presence of mixed content on the current page of the site in developer tools in the browser. The toolbar is opened by pressing the key F12 or a combination Ctrl+Shift+C... Information is displayed in tabs Console and Security:
To rectify the situation, it is necessary to replace the HTTP protocol with HTTPS in all links on the site. Depending on the internal structure of the site and the used CMS, different actions may be required: